Seed coating apparatus

ABSTRACT

A seed coating apparatus for applying a coating fluid to seeds, consists of a seed input, a housing connected to the seed input, the housing having a seed output, a rotating seed dispersing member within the housing receiving seed from the seed input, a device adapted to produce a moving air curtain between the seed dispersing member and the seed output, whereby coating fluid applied to the seeds is kept within the seed coating apparatus by the moving air curtain, a rotating fluid dispensing member between the air curtain producing device and the seed output, and a source of coating fluid entering the housing. The rotating fluid dispensing member may preferably be a rotating bowl with apertures arranged vertically along the periphery, so that the fluid is dispensed along a vertical axis.

BACKGROUND OF THE INVENTION

This invention relates to an apparatus for treating seeds by applying aliquid such as a herbicide or fungicide to the seed.

Seed coating apparatuses typically utilize a cylindrical orfrustoconical housing in which seed is fed into the top of the housingwhich is dispersed in the open interior and falls downwardly though aseed coating region in which dispersed air born droplets of coatingfluid contact and coat the falling seeds.

The prior art devices utilize various means for dispersing the seed anddispensing seed coating fluid in the seed coating region.

U.S. Pat. No. 3,288,052 to Hough discloses a rotating vaned structurewith an open bottom for dispersing seed. A rotating concave platereceives the fluid which is discharged over the upper lip of the plate.The plate has no features to capture the fluid and accelerate it to thespeed of the plate before discharge.

U.S. Pat. No. 2,862,511 to Forsberg discloses a rotating brush fordispensing the fluid. The brush receives fluid which is hurled outwardlyfrom the brush fibers by the centrifugal force provided by the rotation.The seed dispersing portion comprises a non-rotating cone to dispersethe seed.

U.S. Pat. No. 3,912,231 to Weber and assigned to the assignor of theinvention of this application, discloses a rotating plate for dispensingthe fluid. The fluid is poured on the plate and is hurled outwardly bycentrifugal force. Weber discloses flutes in the plate to increase thevertical distance in which droplets are hurled outwardly.

The above prior art means for dispensing the fluid leave room forimprovement in the coating efficiency of the mist produced. Non-uniformdroplets, droplets discharged at less than optimal velocity, unevendensity of the mist in the seed treating region, difficulty in cleaningthe devices, seed coating regions which extend only a minimal distancevertically, and the inadvertent spread of fluid beyond the seed coatingregion are all problems associated with the above apparatuses.

It is highly significant that the fungicides utilized for coating seedsare extremely expensive and can be quite toxic. In order to be optimallyeffective, the fungicide must efficiently coat the entire outer surfaceof each seed with a minimal amount of fluid. Thus, the efficiency incoating seeds, containment of the seed coating fluid in limited areas ofthe apparatus, and having an apparatus which is easily cleanable arehighly desirable features in this type of equipment.

SUMMARY OF THE INVENTION

A seed coating apparatus for applying a coating fluid to seeds, consistsof a housing with a seed input and a seed output, a rotating seeddispersing member within the housing for receiving seed from the seedinput, a fluid dispensing portion between the seed dispersing member andthe seed output, and a device adapted to produce a moving air curtainbetween the seed dispersing member and the fluid dispensing portion,whereby coating fluid applied to the seeds is kept within a seedtreating region by the moving air curtain. The fluid dispensing portionmay preferably be a rotating bowl with apertures arranged verticallyalong the periphery of the bowl, so that the fluid is dispensed in aregion extending along a vertical axis. The device for producing themoving air curtain is preferably a rotating member.

A principal object and advantage of the present invention is that itprovides a moving air curtain between a seed dispersing member and thefluid dispensing member, so that fluid, which may be dispensed in theform of a fine mist, is kept below the air curtain. This prevents theseed dispersing member and the walls of the apparatus above the aircurtain from becoming coated with the fluid, thus allowing easiercleaning of the apparatus and conservation of the fluid. Furthermore,this minimizes the opportunity of fluid from escaping into theenvironment.

Another principal object and advantage of the present invention is thatthe fluid dispensing member may be a rotating bowl with aperturesarranged axially and vertically along its periphery so that the fluid isdispensed along a vertical axis. This provides a larger seed treatingregion and a more even distribution of the fluid than earlier devices.Generally, the prior art devices disperse the fluid in a horizontalplane.

Another object and advantage of the present invention is that it mayinclude a rotating seed dispersing member in the form of an inverted,rotating cone with a plurality of vanes along the cone's surface and afrustoconical housing engaging the vanes. This produces a more evendistribution of seed by causing the seeds to travel along the vaneswhere they are thrown outwardly and fall downwardly in a spiral at theouter periphery of the housing in an even curtain.

Another object and advantage of the present invention is that therotating seed dispersing member and the rotating fluid dispensing membermay be driven by coaxial shafts, thus saving space within the apparatus,improving seed flow and seed treating efficiency.

Another object and advantage of the present invention is that therotating bowl dispenses fluid only through defined apertures. Thisproduces a more even mist than earlier devices, which merely threw thefluid out horizontally with no flow restriction or regulation.

Another object and advantage of the present invention is that the bowlis substantially closed at its top with a non-rotating cap through whichfluid is introduced. The substantially closed bowl keeps the seed out ofthe fluid dispensing portion aiding in maintaining the cleanliness ofthe apparatus. Also, this produces a more even fluid distribution andeconomizes on fluid more than earlier devices, which merely dripped orpoured the fluid onto a rotating disk.

Other advantages of the present invention will be identifiable from thedrawings, detailed description, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front partial sectional elevational view of the apparatus ofthe present invention.

FIG. 2 is a detailed perspective view of the rotating seed dispensingmember of the present invention.

FIG. 3 is a detailed exploded view of the rotating fluid dispensingmember of the present invention.

FIG. 4 is a schematic showing the environment of the present invention.

FIG. 5 is an exploded view of the parts of the present invention.

FIG. 6 is a schematic showing a second embodiment of the air curtainproducing device of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The seed coating apparatus of the present invention is generally shownin the figures as reference numeral 10.

The seed coating apparatus 10 consists of a seed input 12 on a housing14 with an open interior 15 and a seed output 16, a seed dispersingportion 17 configured as a rotating seed dispersing member 18 within thehousing 14, the seed dispersing member 18 receiving seed from the seedinput 12, an air moving portion 20 adapted to produce a moving aircurtain below the seed dispersing member 18, a fluid dispensing portion22 between the air curtain producing device 20 and the seed output 16,and a source 24 of coating fluid entering the housing 14.

Seed is fed into the apparatus 10 at the seed input 12 and travels theapparatus 10 under the influence of gravity. In the preferredconfiguration, the apparatus 10 is therefore vertically arranged. In thepreferred embodiment, the seed input 12 is a vertical duct 12A enteringthe housing 14.

Preferably, the rotating seed dispersing member 18 consists of a cone 30rotating on a first shaft 32. The cone 30 has a surface 34, a rim 36,and a seed dispersing output 37. As seen in the figures, the cone 30converges upwardly within the housing 14. Preferably, the rotating seeddispensing member 18 also includes a plurality of vanes 38 spaced alongthe surface 34 of the cone 30 adapted to direct the seed with therotating seed dispensing member 18. A frustoconical top 40 may engagethe vanes 38 as shown in FIG. 2.

In the preferred embodiment, the air curtain 37 producing device 20 is arotating disk 20A, as shown in FIG. 1. The disk 20A may suitably rotateat a speed of about 1000 rpm. The disk 20A rotates on a second shaft 42.Preferably, the first shaft 32 and second shaft 42 are concentric, asshown in FIG. 1.

Alternatively, as shown in FIG. 6, the air curtain producing device 20may be a fan 20B or the like with blades 20C or with an external sourceof compressed air suitably injected into the region between the seeddispersing member 18 and the fluid dispensing member 22.

In yet another embodiment, the air curtain producing device 20 may beone or more compressed air inlets 20D.

In the preferred embodiment, the rotating fluid dispensing member 22consists of a bowl portion 44 rotating on the second shaft 42 and havinga periphery 48 with apertures 50 whereby the fluid is dispensedoutwardly by centrifugal force at fluid discharge regions 49.Preferably, the third shaft 46 is an extension of and integral with thesecond shaft 42. The disk 20A and the bowl portion 44 then rotate at thesame speed. However, separate shafts could also be used, therebyallowing the disk 20A and bowl portion 44 to rotate at different speeds.Details of the bowl portion 44 are in FIG. 3.

To provide maximum fluid dispersal, it is preferred that the apertures50 be arranged vertically along the periphery 48 into slots 51, definingan upwardly extending discharge region 45 so that the fluid can bedispersed along a vertical axis, that is, along dimension D1 of FIG. 3into a fluid treatment region 53 adjacent to the bowl 44 with the topand bottom borders of the region defined by the dashed lines 55.

The apparatus 10 may also include a stationary cap 52 engaging andsubstantially closing the rotating bowl portion 44, as seen in FIGS. 1and 3. A slight gap 54 between the bowl portion 44 and cap 52 allowsunrestricted rotation of the bowl portion while still preventing seedfrom entering the bowl portion and allowing excessive levels of fluid inthe bowl to escape.

A source 55 of coating fluid 24 is preferably a fluid duct 60 enteringthe stationary cap 52. The duct 60 communicates with vertical tubes 62within the bowl portion 44, thereby delivering fluid to the interior ofthe bowl portion 44.

As best seen in FIG. 3, the apparatus 10 also may preferably include ascreen 70 on the bowl portion 44 having a plurality of holes 72 therein.Some of the holes 72 are aligned with apertures 50 in the bowl fordispensing the fluid. The screen may preferably be constructed ofstainless steel. The screen 70 rotates with the bowl portion 44. Thescreen may be replaced and interchanged to provide varying mistingparameters of the fluid dispensing member such as droplet size andvolume.

The screen forms an outer fluid restriction wall 71 for interiorcompartments 73 that extend radially inward. The compartments 73 capturethe fluid before it discharged thru the apertures, thus effectivelyaccelerating the fluid to the approximate velocity of the rotating bowlportion 44. This apparently allows the fluid to discharge at a highervelocity creating a finer and a more dense mist than the prior art fluiddispersing portions configured as plates or bowls which allowed thefluid to move circumferentially on the plate or bowl prior to discharge.

FIG. 5 is an exploded view of the apparatus 10, showing its componentparts. The first shaft 32 is driven by a first motor 80, and the secondshaft 42 is driven by a second motor 82. Torque from the motors 80, 82may be transmitted to the shafts 32, 42 by any suitable power transfermeans (the figures show the use of belt 84 and chain 85 for thispurpose).

FIG. 4 shows the environment of the apparatus 10. Seed falling out ofthe seed output 16 may preferably fall onto a conveyor 90 for transportto a further location.

The operation of the apparatus 10 illustrates its advantages. Seedenters the apparatus 10 through the seed input 12, under the influenceof gravity. The falling seed then encounters the rotating seeddispersing member 18. The seed hits the surface 34 of the inverted cone30 or the vanes 38 and then travels toward the seed dispersing output 37as the cone 30 rotates. The vanes 38 channel the seed in a circulardirection as it falls. The frustoconical housing 40 keeps the seedswithin defined channels. As the member 18 rotates, it thus produces aneven distribution of seed causing the seed to pass in an even curtaintumbling and falling in spiral direction through the seed treatingregion.

Below the member 18, the air curtain producing device 20 produces amoving air curtain through which the seed falls in a downward spiral.

The seed then encounters mist from the fluid dispensing member 22, whichevenly coats the seed as it falls through the mist. The spinning andtumbling action of each individual seed as it passes in a spiraldirection through the seed treating region facilitates the completecoating of each individual seed. Because of the seed action and theunique construction of the fluid dispensing member 22, i.e., a bowl withvertically arranged apertures 50, the seed is more efficiently andevenly coated with mist than in previous devices, which merely threw thefluid out horizontally in a narrow seed treating region.

The moving air curtain keeps the mist below the air curtain and themember 18. This prevents the walls of the apparatus 10 above the aircurtain from becoming coated with the fluid, thus allowing easiercleaning of the apparatus. This also helps to prevent the fluid, whichmay be toxic, from escaping into the environment such as where fluidflow would be inadvertently left on when the grain is not being fed intothe device.

The inventor has found that utilization of the above invention providessignificantly more complete coating of each seed while utilizing lessfungicides. Appropriate rotational speeds are 90 r.p.m. for the seeddispersing member and 3600 r.p.m. for the bowl portion.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof, and it istherefore desired that the present embodiment be considered in allrespects as illustrative and not restrictive, reference being made tothe appended claims rather than to the foregoing description to indicatethe scope of the invention.

I claim:
 1. A seed treating apparatus for applying a fluid to seeds, theapparatus comprising:a housing with an upwardly positioned seed input,an open interior below said seed input and a seed output; a rotatingseed dispensing portion positioned below the seed input and having asubstantially vertical axis; a fluid dispensing portion positioned belowthe seed dispensing portion, the fluid dispensing portion having asubstantially vertical axis and comprising a rotating bowl portionhaving a substantially cylindrical and substantially upright rotatingwall with a plurality of openings in said wall for dispensing the fluidfrom a vertically extending region through said wall, and a fluid supplyduct extending to the fluid dispensing portion.
 2. The seed treatingapparatus of claim 1 wherein the rotating bowl portion has a pluralityof upright fluid dispensing regions.
 3. The seed treating apparatus ofclaim 1 wherein the rotating bowl portion has a plurality of upwardlyextending slots for capturing and rotating the fluid before said fluidis discharged from the fluid dispensing portion.
 4. The seed treatingapparatus of claim 1 further comprising a plurality of fluid capturecompartments to capture and rotate the fluid before said fluid isdischarged from the fluid dispensing portion, each compartment having anexterior compartment wall for restricting the outward passage of thefluid, the wall having at least one aperture for discharging said fluid.5. The seed treating apparatus of claim 4 wherein the compartmentcomprise upright slots in the bowl portion and the exterior compartmentwall at each compartment has a plurality of upwardly spaced aperturesfor discharging the fluid.
 6. The seed treating apparatus of claim 1wherein the bowl has an open top and further comprises a non-rotatingcover portion substantially closing said open top.
 7. A seed coatingapparatus for treating seed with a fluid, the apparatus comprising:ahousing with an input, and open interior and an output; a rotating seeddispensing member having a substantially vertical axis and positioned inthe open interior below said input; a fluid dispensing portionpositioned in the open interior and comprising a substantially closedcontainer with a substantially upright and apertured outer fluidrestriction wall rotating about a substantially vertical axis; and, afluid supply duct extending to the fluid dispensing portion andconnecting to a fluid source for providing fluid to the fluid dispensingportion.
 8. The seed coating apparatus of claim 7 wherein the fluiddispensing portion comprises a rotating bowl portion with an open top,and a non-rotating cover substantially covering the open top, whereinthe rotating bowl portion comprises the rotating apertures outer fluidrestriction wall.
 9. A seed coating apparatus comprising:a housing withan upper seed input, an open interior below said seed input, a seedoutput below said open interior; a rotating seed dispensing member belowthe seed input in the open interior; a rotating fluid dispensing portionbelow the rotating seed dispensing member, the fluid dispensing portionhaving a rotating upright outer fluid restriction wall withcircumferentially and axially spaced apertures with a plurality ofcompartments extending radially inwardly from said fluid restrictionwall for capturing and rotating the fluid in the fluid dispensingportion before the fluid is discharged from the apertures; and a fluidsupply duct extending to the fluid dispensing portion and connecting toa fluid source for providing fluid to the fluid dispensing portion. 10.A seed treating apparatus for applying a fluid to seeds, the apparatuscomprising:a housing with an upwardly positioned seed input, an openinterior below said seed input and a seed output; a rotating seeddispensing portion positioned below the seed input and having asubstantially vertical axis; a fluid dispensing portion positioned belowthe seed dispensing portion, the fluid dispensing portion having asubstantially vertical axis and comprising a rotating substantiallyclosed bowl portion having an upwardly extending, substantiallycylindrical wall with a plurality of axially spaced openings in saidwall for dispensing the fluid from a vertically extending region; and, afluid supply duct extending to the fluid dispensing portion.
 11. Theseed treating apparatus of claim 10, wherein the rotating bowl portionhas a plurality of upwardly extending slots positioned radially inwardlyfrom the axially spaced openings in the substantially cylindrical wall,for capturing and rotating the fluid before said fluid is dischargedfrom the axially spaced openings of the fluid dispensing portion. 12.The seed treating apparatus of claim 10, further comprising a pluralityof rotating fluid capture compartments to capture and rotate the fluidbefore said fluid is discharged from the axially spaced openings, eachcompartment having an exterior compartment wall for restricting theoutward passage of the fluid, the wall having at least one aperture fordischarging said fluid.